You're in the flow: writing code, experimenting in the REPL, running tests ... and then it happens: an exception. Clojure approaches a kind of ideal coding environment, right up until something goes wrong. Clojure stack traces are notoriously challenging: hard to read, lots of noise, and limited in context. Fortunately, we have the tools to fix this! We'll describe Pretty: a library that presents exceptions ordered and formatted for readability, and Tracker: a library to provide context to exceptions that goes beyond the stack trace.

4) Sane, smart, fast, Clojure web services with Rook
Rook (the name is a play on Bishop) is a library that fits into Ring as a straight-forward, easy way to build web services. In essence, Rook is a mapping between web resources and specific Clojure namespaces.Rook leverages conventions, metadata, and a few strong opinions to make it fast and easy to build well structured web services, following the REST pattern ... and goes beyond just request dispatching, providing some much needed infrastructure that helps you build code that is concise, efficient, testable, and maintainable..